


When Stress Is Applied to the System, I Lean More Toward Loving You

by snazzy_scarf



Category: Haikyuu!!
Genre: Aged-Up Character(s), Fluff, Kogane is secretly a science nerd, Light Angst, M/M, Science, Study Date, lots of science, they're in college
Language: English
Status: Completed
Published: 2020-03-16
Updated: 2020-03-16
Packaged: 2021-02-28 19:55:16
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,947
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23172790
Author URL: https://archiveofourown.org/users/snazzy_scarf/pseuds/snazzy_scarf
Summary: When Goshiki had invited his boyfriend over to help him study for his chemistry final, he’d expected many things to happen.What he had not expected was for Koganegawa to show up at his apartment at nine in the morning with a whiteboard and an excited grin on his face.
Relationships: Goshiki Tsutomu/Koganegawa Kanji
Comments: 5
Kudos: 115





	When Stress Is Applied to the System, I Lean More Toward Loving You

**Author's Note:**

> I am once again writing kogagoshi for an exchange gift sdbfshdf  
> I had fun writing this! These two are always fun to write so I hope you enjoy!

When Goshiki had invited his boyfriend over to help him study for his chemistry final, he’d expected many things to happen. He’d expected to have Koganegawa arrive sometime in the afternoon and the two of them would get lunch together. He’d expected for them to actually start studying around three o’clock, and then eventually get sidetracked by six and start talking about random things together as the sun set. Goshiki knew his boyfriend, he knew himself, and he knew how the two of them worked together. His request for academic aid would quickly fall into a regular old date with some minor productivity mixed in. It was expected, it was inevitable, it was foolproof.

What Goshiki had not expected was for Koganegawa to show up at his apartment at nine in the morning with a whiteboard and an excited grin on his face. 

“So now that we know all about how galvanic cells work, let’s see how we can actually apply that energy! Take a car battery for example: it’s made up of six lead based cells that add up to 12 volts of energy—or 12.6, more precisely—that all work together to power the parts of your car, like your lights, your radio, and all the other fancy stuff you might have. The electrons move through the wires in your car to reach the parts you're using, and continuously react to supply everything you need! But you’re probably wondering, ‘So what happens when the battery runs out of power?’ Well, that’s where the alternator comes in! See, the reason that car batteries are able to run for as long as they do are all because the alternator charges them once you turn on your car! Now, how does it work you say? Well, that’s the fun part…”

Goshiki sat on his bed mindlessly nodding along with what Koganegawa was saying, barely keeping up with it all. It was now around noon, and his bedroom had been transformed into a chaotic mess of paper and marker with formulas and equations and diagrams scattered about. They’d started studying the moment Koganegawa had arrived, and hadn’t stopped since. The second Goshiki had mentioned the word “electrochemistry,” his boyfriend had jumped up with sparkles in his eyes and begun an extensive lecture on the topic. 

It was absolutely adorable how giddy he was, Goshiki just really wished he could understand half of what he was saying.

“And through the power of magnetization, the alternator is able to supply more electrons to the battery so that the reactions in the cells don’t reach equilibrium as quickly as they normally would! And if there’s any electrons left over, the lead-storage battery is able to live up to its name and store them for later use, that way no energy is wasted.”

Koganegawa pointed to the whiteboard behind him that was covered in drawings of galvanic cells, with dry erase marker lines strewn across the entire surface, detailing the path of the electrons. It would have been an unreadable mess to anyone who hadn’t been paying attention to each addition over the past hour, but luckily for Goshiki, he’d already zoned out five minutes in. 

Koganegawa stood smiling at him with expecting eyes, holding a marker in his hands eagerly, and Goshikki realized that he’d been asked a question. 

“Sorry, what?” He stumbled, hoping his cluelessness wasn’t too apparent.

“I asked if you had any questions.” Koganegawa told him, “I know this is probably just a lot of review for you, so it’s ok if you want to shift to a different topic.”

Goshiki didn’t tell him that he’d actually forgotten the majority of the subject throughout the year, and any “review” was practically new information to him. Instead, he used this to his advantage to try and change the topic to something he might actually be able to understand.

“Uh, yeah, I get a lot of this already so uh, maybe we could talk about equilibrium? That’s easy, right, it’s just whenever the reaction stops?” He said, hoping that he didn’t sound completely lost.

“Huh?” Koganegawa’s smile dropped for a second and he blinked. Then he quickly popped back to life again and spun around to erase the electrochemistry he’d drawn. “Oh no! No, no, no, no, that’s not it at all!” He finished erasing the diagrams from earlier and scribbled down something new. Goshiki leaned to the side to try and see what it was as his cheeks heated up from embarrassment. 

Koganegawa turned around with a nervous grin on his face and looked down at where Goshiki was sitting, tapping the marker in his hand repeatedly. “Ok, so if there’s one thing you need to absolutely know about equilibrium is that the whole point of it is that it  _ never _ stops.”    


“Oh.” Goshiki muttered, feeling like an idiot. 

“It’s okay!” Koganegawa said, waving his hands in reassurance, “it’s okay, it’s a common misconception. That’s why we’re here! To make sure you understand things correctly.” 

Goshiki pouted and nodded along, looking off to the side.  _ I really wanted you here so that we could go out on a date, but okay.  _ He thought, keeping his wishes to himself. He turned his gaze back to the white board where his boyfriend had circled the arrows in the equation he’d written.

“So the two arrows signify the back and forth reactions of the equation, and basically tells you that the equation is both forming products and reactants at the same time. So pretty much any compound in the equation is both a product  _ and  _ a reactant all at once, but not always. Understand?”

Goshiki stared at him blankly and shook his head.

“Uh, okay, um…” Koganegawa fumbled and tapped his marker across his hand faster. “Don’t worry, it’ll click for you soon, maybe just um, oh! Maybe you just need an example!” He smiled again and turned to write another equation on the board. “You’re familiar with the Haber Process, right?” 

Goshiki shook his head again, feeling more and more out of the loop by the second. 

“Okay, well, this should help then. Let’s take a quick break from chemistry…” Koganegawa erased the board and took out a different color marker. “Aaaand, I’ll give you a little history lesson!”

Goshikki had to stop himself from slamming his head onto his notebook.

“Don’t worry, it’s fun, I promise! Well, maybe not entirely fun, because a lot of people died, but that’s not what we’re focusing on!” Koganegawa didn’t notice his boyfriend’s dismay and continued on through his lecture, Goshiki quickly zoning out and staring at the wall behind him.

He hadn’t expected this  _ at all.  _ All he’s wanted was for a fun, chill study date with his boyfriend, but instead he’d gotten thrown into a crash course video with no pause button. He loved his boyfriend to death, and he thought it was the cutest thing in the world how eager Koganegawa wanted to help him, but Goshiki didn’t want help!! He’d already accepted that he was going to fail his exam, he just wanted to have some excuse that he’d tried to study when he’d actually just gone on a date with his boyfriend! They were supposed to have thrown out the books and cuddled by now! 

Goshiki sighed and stared down at his notebook that was only barely a page full of notes and tried to tune into what Koganegawa was saying again. Maybe he should just give up on his perfect date plan and actually try to learn. He glanced up at Koganegawa, who’d practically filled the whiteboard up with equations again, and tried to listen to him.

“So now we can use Le Chatelier’s Principle to determine which side of the reaction will be favored under certain conditions! So let’s say you had a balloon filled with nitrogen and hydrogen gas in equilibrium. If you raised the temperature and kept all other conditions constant, which side would it lean towards?”

Goshiki shrugged half heartedly and shook his head.

“Well, because the process is exothermic, a rise in temperature would put the decomposition reaction in unfavorable conditions, so instead it would start to move backwards to favor the synthesis reaction instead. Now let’s take it a different direction and instead say that we changed the volume. If the volume of the balloon is increased…” 

Goshiki looked down at his paper and started to zone out again. Welp. No one could say he didn’t at least try to get back into it. He sighed and rested his cheek against the palm of his hand, propping his elbow up on his leg. He really wanted to spend time with his boyfriend, really he did, but for the first time since they’d started dating Goshikki actually felt bored. Not with Koganegwa, but well, sort of. He frowned to himself and glared at the floor. This just wasn’t what he’d wanted at all! He’d invited his boyfriend over to have some fun, how was he supposed to know that he secretly loved chemistry? Usually he loved to listen to his boyfriend talk but this didn’t feel like fun conversation, it just felt like a lecture. 

Goshiki continued to look down at his paper and pout, until he noticed that the room had gone quiet. He glanced up and saw that Koganegawa had stopped talking and was looking down at him with uncertainty. 

“Oh, sorry, I uh, I didn’t hear the question.” Goshiki mumbled, looking away sheepishly.

“I didn’t ask anything.” Koganegawa said, laughing weakly. 

“Oh.” 

The two of them sat in awkward silence for the next several seconds. 

“Tsutomu, are you okay?” Koganegawa asked, looking down at his boyfriend with worry. “You haven’t really been saying anything.”

“Oh no, I’m okay! I’m just, uh…” Goshiki trailed off, trying to think of something to say that wouldn’t hurt Koganegawa’s feelings. “This is a lot to take in at once, y’know?” 

Koganegawa looked at him for a moment, and then turned to glance at the board behind him. He looked around the room at the mess of papers and fell quiet. “Oh… oh yeah, I guess I’ve uh… I guess I’ve really been talking a lot for the past hour or so haven’t I?” He laughed nervously and fiddled with the marker in his hands.

“It’s actually been about three hours now.” Goshiki told him, and immediately wished he’d kept his mouth shut when he saw his boyfriend’s bubbly demeanor go flat. 

“Ah…” Koganegawa muttered and looked anywhere but at Goshiki. “I didn’t realize how long it’d been. I’m sorry.” 

Goshiki looked up at his boyfriend with guilt weighing on his chest. He didn’t want to make him feel bad! He slowly stood up from where he was sitting on his bed and walked over to Koganegawa. He gently took his hand and guided him back to the bed to sit down. Koganegawa sat and looked off to the side. 

Goshiki opened his mouth to say something that would cheer him up again, but nothing came. He looked at him helplessly for a few seconds and gave up on words, instead leaning forward to give him a loose hug. Koganegawa tensed up slightly for a moment, but leaned back into him all the same. The two of them were silent for a few minutes. 

“I’m sorry if I’ve been wasting your study time,” Koganegawa said, “I just got so excited when you asked me to help you with chemistry that when I started to talk about it I kinda forgot about the whole ‘helping you’ part and started to do my own thing.” 

Goshiki hugged him tighter and shook his head, “no no, you haven’t been wasting my time at all.”

“But you asked me here to help you study, and I haven’t been helping you, I’ve just been confusing you.”

“That’s not… I’ve been getting confused because I haven’t been paying attention, that’s not anything to do with you. You’ve been trying to help me the best you can, you haven’t done anything wrong. And besides, I… didn’t really have any interest in learning about chemistry today anyway…”

“Huh?” Koganegawa broke away from their hug and looked down at Goshiki in confusion. “But I thought you wanted to study today?” 

Goshiki looked away sheepishly and gave a weak laugh. “Well uh, yeah, I sort of just told you that so you would come over. I was kinda hoping we’d get sidetracked and do something else.” 

“Oh.” Koganegawa muttered. “Wait, so you didn’t want to study at all?”

“Well, not exactly, I mean, I guess I wanted to study for a little bit, but mostly I just wanted to spend time with you.” 

Koganegawa was silent for a moment as he stared across the room. Then he let out a huff and fell backward onto the bed. “Tsutomu.” He looked up at his boyfriend with an amused glare. “If you wanted to go out on a date today why didn’t you just tell me?” 

“Um. Uh… Well I uh,” Goshiki tensed up and looked away, smiling sheepishly. “Y’know I um… I wanted it to happen naturally, I uh, um…” His face turned red as his plans for the day were figured out. 

Koganegawa sighed and looked up at the ceiling, “What am I going to do with you, Tsutomu?” He laughed.

“I’m sorry…” 

“You could’ve just told me that you wanted to go out instead of making me ramble about science for three hours.” Koganegawa teased, sitting up again and looking at him with a knowing smile on his face. 

“Well I didn’t want to stop you, you looked like you were having fun. I didn’t know you liked science so much, it’s cute how happy you got when you started talking about it.” 

It was Koganegawa’s turn to start blushing now, and he smiled, turning away. “No it’s not, don’t say things like that.”

“But it is!” Goshiki laughed, leaning closer to him and smiling. “I’ve never seen you get that giddy before, it was adorable! You get so wrapped up in what you’re explaining that you start to get this expression on your face like you know just how smart you are and you’re gonna show off to the world. It’s cute!” 

Koganegawa’s face grew redder and he hid it in his hands. “Tsutomu…” he whined.

“Kanji…” Goshiki teased back, laughing and wrapping his arms around his boyfriend. “I’m sorry I tricked you into teaching me chemistry. I was just annoyed because I didn’t understand it, not because of you.” 

“Well I still want to help you get it, but I know you’d rather we go out and do something else instead.” 

“How about this: we go out and have some lunch and you can tell me all about your favorite sciency-things.” 

“Are you sure? I don’t want to bore you again…”

“You won’t, I promise. As long as I don’t have to take any notes and can just focus on your pretty face then there’s no way I could ever get bored.” 

Koganegawa stared wide-eyed at his boyfriend, face completely flushed. He stuttered out something incoherent and Goshiki laughed at him, reaching down to take his hand. Koganegawa smiled sheepishly and looked to the side. “Okay, we can do that. But only on one condition.”

“And what’s that?” Goshiki asked, giggling. 

“Close your eyes.” 

“What?”

“Close your eyes just real quick.”

“Okay…” Goshiki agreed and hesitantly closed his eyes. He waited in silence for a few seconds and then felt something soft press against his cheek. He opened his eyes just in time to see his boyfriend pulling away from him with a smirk. Goshiki blushed and skwaked in protest. 

“Kanji, you can’t just do something like that without warning!!” 

“If you get to make me flustered then I get to make you flustered, it’s only fair.” Koganegawa stated and looked at him with a satisfied smile. Goshiki stuttered and looked away from him, standing up and crossing his arms.

“Whatever, let’s just go get something to eat.” He mumbled, trying to look upset, but unable to keep a smile off of his face. Koganegawa agreed and stood up as well, patting his pockets to make sure he had his phone before following his boyfriend to the door. Goshiki grabbed his own phone and led the two of them out. “So, what’s your favorite thing about science that you wanna talk about?” He asked.

“Hmm, well I think entropy is pretty cool.” Koganegawa answered, his happy demeanor from earlier slowly returning. “It’s basically the universe’s inherent tendency to be chaotic and warm, which plays a huge role in thermodynamics and whether or not a reaction will happen by itself or not. Y’know that stuff about Le Chatelier's Principle I was talking about earlier? Well, it sort of applies here, except that the favored side of a reaction is based on the number of moles and the state of matter rather than the stress that’s put on a system. So for example let’s go back to the Haber Process and why it was so important…”

Goshiki smiled as the two of them left his apartment. Koganegawa’s excitement had returned, and the happy expression on his face was endearing as he gestured in front of him while he gave his explanation. Goshiki still didn’t have a good understanding of what he was saying, but he didn’t mind too much anymore. It made his boyfriend happy to talk about science, and it made Goshiki happy to see him happy, so it was a win-win. He might not pass his chemistry exam with flying colors, but at least it helped him get closer with his boyfriend. 

**Author's Note:**

> Thanks for reading! Maybe Kogane was able to teach you something with his rambling or maybe you felt just as helpless as Goshiki, but regardless I hope you enjoyed! I always love writing for these two and I'm glad to contribute to the tag once again!


End file.
